An Early History of Computer Viruses

Alan Tilley, 21 September, 2008

In the early 1980s shortly after the introduction of the IBM PC many clones began to appear on the market, the Amstrad was affordable and became ubiquitous. The first Amstrad PC was the 1512. The 512 indicated the amount of RAM in kilobytes and the preceding “1” was the model number. Some of these machines had one 5¼” floppy 360 kb drive but the most popular came with two 5¼” drives. Hard drives were not normally available and it was usual to boot-up with a write protected floppy in drive one and have data stored on drive two. The ability to write protect ensured that no unwanted files could be written to floppy disks.

The internet as we now know and use it did not exist at this time, so in the '80s computer users were not concerned with the problem of viruses. The definition of a virus is a short hidden routine that has the capability of copying itself; and at the time in Bulgaria it was a requirement for computer science degree students to be able to write a virus. Any infection from viruses came from unprotected dubious floppy disks which transmitted the unwelcome code onto the computer RAM which would in turn infect any other unprotected disks used on that computer before it was switched off.

In January 1988 there were 3 known viruses circulating; a year later in January 1989 there were 8. By January 1990 the number had risen to 35, January 1991 just under 300 and by July of the same year the number of viruses had risen to over 700. This increase slowed down during the summer months due to computing then being more of a winter pastime. Many of the early computer viruses were not dangerous from the data loss point of view, and could be seen as amusing (when on somebody else’s computer), and were of the “Kilroy was here” type. Some of these amusing viruses included:-

• Dark Avenger At random, a message would appear:

EDDY LIVES - SOMEWHERE IN SPACE

• Dot Eater Eats every “.” that was typed together with a sound effect.
• Fumble If a speed of more than 60 wpm was used when entering data, occasionally letters were changed. This only happened on even dates in the month.

• Keytrick Every 256th keystroke had a 1 in 4 chance of being ignored.
• Stoned Every 8th time a the computer was booted a message was displayed:

  YOUR PC IS STONED
  LEGALISE MARIJUANA

• Eight Tunes 91 days after the infection 1 of 8 tunes were played and repeated every 30 minutes.
• Green Caterpillar 2 months after infection a green caterpillar worked its’ way across the screen from left to right and ate the letters dropping them out of it’s rear 10 characters to the left converted to yellow on black.
• Kitty No damage is done, but a message appeared “Sorry this is not a system disk”. The message could be ignored and the disk used normally
• F-You On the screen the obvious message was displayed and after a few minutes disappeared when work could continue. This was repeated every hour.
• Cascade In a word processing program after 10 enter key presses letter would start to fall. The whole document finishing as a random pile of letters at the bottom of the page.

Other early viruses were more malicious and included:

• Brain Replaced the boot sector with its own code. No damage was done apart from slowing the computer down and taking 7 kb of RAM, a considerable amount in those days
• Victor On Wednesdays between 9&10 am, 1&2 pm and 3&4 pm, the virus deleted all the files in the current directory (these days known as a folder).
• Casino On 15 January, April and August, the virus copied the FAT into RAM and over-wrote the original FAT with rubbish. It then displayed the message: In the unlikely chance that you won, the following message appeared:

I HAVE DESTROYED YOUR FAT
IF YOU SWITCH OFF NOW YOUR DATA WILL BE LOST
PLAY JACKPOT
You have three chances to guess a 3 figure number

In the unlikely chance that you won, the following message appeared:

BASTARD, YOU’RE LUCKY THIS TIME
SWITCH OFF YOUR COMPUTER AND DON’T TURN IT ON UNTIL TOMORROW

There were many more viruses but the above is a taste of what computing was like in the early days. As computers developed and hard disks became standard, the control and the spread of viruses rapidly increased and latterly the use of the internet meant that it is a hazard that we all have to live with.

Remember the old adage “Prevention is better than Cure”